Can someone please double check my thermofan wiring? Thanks

[Cressid@]

Hey peeps,
ive searched and read the guide on how to wire up thermofans by The Witzl. But im alittle confused.

So the car is a mx83+1jzgte+emu. I removed the hydraulic fan and replaced it with a 2jzgte waterpump.

Now heres my problem, a mate of mine said the way i was planning to wire up my fans is incorrect so i thought id just double check with you gurus.

My radiator had a water temp sender screwed into the bottom end tank. When i located it, it seemed to be already unplugged. Not sure if it was needed and even working so i just unscrewed it and replaced it with a Tridon open type thermo switch. TFS139 Temp Range 85 -80
I then grounded my radiator so when the temp hits 85 degrees, it grounds the switch thus turning on both fans

Now ive attached the diagram on how im going to wire it up can anyone just double check to see if what ive done is correct?.

Thanks in advance

[pandaah]

whats wrong with that?... looks like it would work to me

[TRD-12A]

Yes that will work fine, the tridon switch you have is it single pin or double pin? if single i recomend running relays with a resistor otherwise you will burn out the switch not straight away but it will happen or you can do what i did and have earth powered relays if your interested ill show you how to do it just let me know

[Cressid@]

Thanks guys
TRD 12A
yeah it is a single pin. If possible can you send me a diagram of how I would set it up with the resister type relay

Thanks buddy

[timbosaurus]

1 x 40A relay should be fine for 2 fans also.

[TRD-12A]

the resistor relay is the same wiring just it has a resistor inbetween pin 86 and 85 internally everything else is the same

[Grega]

it will work on the proviso the TFS139 is a NO (normally open) type switch which you've stated to be the case. as folks have suggested a resistor/diode (to protect) type relay is best for these kinds of setups.

[Cressid@]

awesome!! ill get cracking at it..

Thanks to TRD 12A he has supplied the wiring..just in case anyone else needs a hand
Pin 30 constant earth through a fuse(straight to body or battery watever is easier), pin 85 + ignition supply, pin 86 earth trigger from sensor, pin 87 earth trigger out to thermo fan. Then you run + ignition straight to thermo fan through a fuse and your done


by the way will one 40 amp resister type relay be sufficient for both fans?

[Grega]

no. both fans should have their own relay as they will burn out 1 relay only.

[Cressid@]

thanks for everyones help!

[timbosaurus]

no. both fans should have their own relay as they will burn out 1 relay only.

Not because of the current they won't. Is there another reason?

[blakeg]

start up current will burn the contacts eventually. but i have done it on a car with no issues over 2 years

[Grega]

as blake suggested - startup current. if you look at the thermo fan thread (the original one) they were measured at startup to pull quite a bit.
found it : here : http://www.toymods.org.au/forums/sho...&postcount=135

[timbosaurus]

Yeah, increased in-rush current of a brushless DC motor is obvious, and my post about 'current' above means both steady state and inrush

But I can guarantee that even the startup current of 2 cooling fans will not damage a genuine 40A relay.

Most 40A ISO mini relays are rated at around 100A inrush current (when used as normally open), and the worst cooling fan I have measured has been 11A steady state, 40A inrush.

I have also ran several setups with 2 cooling fans off one relay for years without incident.

Hey, if you're concerned, run two. There is no harm.

If you don't have the space or don't want the slight complexity increase, one will be fine.

[TRD-12A]

yeah a single relay will be fine have done many cars with a single relay and never had a problem 40A is alot of amperage if you are curious about it you can get an amp guage to test and see what amperage it is using and then determine how many relays but honestly 1 will be fine.